Conventionally, an acetoacetyl group-containing polyvinyl alcohol resin (hereinafter sometimes abbreviated as “AA-PVA”) obtained by acetoacetylating a polyvinyl alcohol resin (hereinafter sometimes abbreviated as “PVA”) is proposed. It is known that the AA-PVA is excellent in water resistance due to high reactivity with various crosslinking agents. Exemplary AA-PVA production methods hitherto proposed are as follows:
(1) An AA-PVA production method which involves a reaction between a PVA and diketene in the presence of a fatty acid ester (methyl acetate) and an acid anhydride (acetic anhydride) (PTL 1);
(2) An AA-PVA production method which involves a reaction between a PVA and diketene in the presence of an organic acid (acetic acid) and an acid anhydride (acetic anhydride) (PTL 2);
(3) An AA-PVA production method which involves a reaction between a PVA and diketene in the presence of an organic acid (acetic acid) and water (PTL 3);
(4) An AA-PVA production method which uses a powdery PVA having an average particle diameter of 250 to 1000 μm and including particles each having a particle size of not greater than 150 μm in a proportion of not greater than 20 wt % (PTL 4); and
(5) An AA-PVA production method which includes the step of drying any of the AA-PVAs produced by the aforementioned methods in a reduced pressure atmosphere at 100 mmHg (PTL 5).